NationMaster - Encyclopedia: Period (periodic table)

In the periodic table of the elements, a 'period' is a horizontal row of the table. For a diagram of the periodic table, see standard periodic table below. ... The periodic table of the chemical elements A chemical element, or element for short, is a type of atom that is defined by its atomic number; that is, by the number of protons in its nucleus. ...

The elements are laid out in a series rows so that those with similar properties line up in vertical columns: this reflects the periodic recurrence of similar properties as atomic weight increases. ...

Modern quantum mechanics explains these periodic trends in properties in terms of electron shells. As atomic number increases, electron shells are filled in roughly this order. The filling of each shell corresponds to a row in the table. Fig. ... [[Image:Valence shell 011 Sodiumup of one or more electron subshells, or sublevels, which have two or more orbitals with the same angular momentum quantum number l. ... It has been suggested that List of elements by atomic number be merged into this article or section. ...

Hence the structure of the periodic table. Since the valence electrons determine chemical properties, those tend to be similar within periodic table groups. In chemistry, valence electrons are the electrons contained in the valence shell of an atom, and which are likely to participate in a chemical reaction through bonding with other atoms or molecules. ... A periodic table group is a vertical column in the periodic table of the chemical elements. ...

Elements adjacent to one another within a group have similar physical properties, despite their significant differences in mass. Elements adjacent to one another within a period have similar mass but different properties.

Category: Periodic table For a diagram of the periodic table, see standard periodic table below. ... This is a standard display of the periodic table of the elements. ... The alternative table is a standard periodic table rotated counterclockwise and then mirrored across the vertical axis, hence like in many writing systems, the lower groups are to the left and the number increases to the right. ... Category: ... The Detailed Table is a smaller version of the Huge Table. ... The text-only table is a version of the Huge Table designed for printing atomic mass data. ... The large version of the periodic table set out below does not fit into some computer screens; however, with a small font size and/or in landscape mode, it may be possible to print this periodic table on one or two normal-size sheets of paper. ... Color coding for atomic numbers: Elements numbered in blue are liquids at Standard Temperature and Pressure (STP); those in green are gases at STP; those in black are solid at STP; those in red are synthetic (all are solid at STP). ... Color coding for atomic numbers: Elements numbered in blue are liquids at Standard Temperature and Pressure (STP); those in green are gases at STP; those in black are solid at STP; those in red are synthetic (all are solid at STP). ... In chemistry, valence, also known as valency or valency number, is a measure of the number of chemical bonds formed by the atoms of a given element. ... This is a version of the periodic table of the elements that places all elements in the same rows. ... An extended periodic table was suggested by Glenn T. Seaborg in 1969. ... electron numbers indicate subshells that are filled to their maximum. ... Categories: ... Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ... Alternative periodic tables are chemical element displays different from the well known Mendeleev periodic table. ... This is a list of chemical elements, sorted by name and color coded according to type of element. ... // This is a list of chemical elements by symbol, including the current symbols used to identify the chemical elements as recognized by the International Union of Pure and Applied Chemistry, as well as proposed and historical symbols. ... A table of chemical elements ordered by atomic number and color coded according to type of element. ... This is a list of the chemical elements, sorted by boiling point measured at normal pressure. ... This is a list of the chemical elements, sorted by melting point measured at normal pressure. ... This is a list of the chemical elements, sorted by density measured at standard temperature and pressure. ... Hydrogen = 1 List of Elements in Atomic Number Order. ... A group, also known as a family, is a vertical column in the periodic table of the chemical elements. ... The alkali metals are the series of elements in Group 1 (IUPAC style) of the periodic table (excluding hydrogen in all but one rare circumstance): lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). ... The alkaline earth metals are the series of elements in Group 2 (IUPAC style) of the periodic table: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and radium (Ra) (not always considered due to its radioactivity and very short half-life). ... A Group 3 element is an element in periodic table group 3 (IUPAC style) in the periodic table, which consists of: scandium (21) yttrium (39) lanthanum (57) - lutetium (71) actinium (89) - lawrencium (103) All of these elements are classed in Group 3 because their outer shell holds three electrons. ... A Group 4 element is an element in periodic table group 4 (IUPAC style) in the periodic table, which consists of: titanium (22) zirconium (40) hafnium (72) rutherfordium (104) All of these elements are classed in Group 4 because their valence shell holds four electrons. ... A Group 5 element is the series of elements in group 5 (IUPAC style) in the periodic table, which consists of vanadium (V), niobium (Nb), tantalum (Ta), and dubnium (Db). ... The group 6 in the periodic table consists of the elements chromium (24) molybdenum (42) tungsten (74) seaborgium (106) Group 6 is the new IUPAC name for this group, the old style name was group VIA in the old European system or group VIB in the old US system. ... A Group 7 element is an element in periodic table group 7 (IUPAC style) in the periodic table, which consists of: manganese (25) technetium (43) rhenium (75) bohrium (107) All of these elements are classed in Group 7 because their valence shell holds four electrons. ... A Group 8 element is an element in periodic table group 8 (IUPAC style) in the periodic table, which consists of: Iron (26) Ruthenium (44) Osmium (76) Hassium (108) All of these elements are classed in Group 8 because their valence shell holds four electrons. ... The Group 9 elements are: Cobalt (27) Rhodium (45) Iridium (77) Meitnerium (109) Color coding for these atomic numbers: At room temperature, all are solid; red indicates item is synthetic and does not occur naturally. ... The Group 10 elements are: Nickel (28) Palladium (46) Platinum (78) Darmstadtium (110) Color coding for these atomic numbers: At room temperature, all are solid; red indicates item is synthetic and does not occur naturally. ... A Group 11 element is one in the series of elements in group 11 (IUPAC style) in the periodic table, consisting of transition metals which are the traditional coinage metals of copper (Cu), silver (Ag), and gold (Au). ... The Group 12 elements are: Zinc (30) Cadmium (48) Mercury (80) Ununbium (112) Color coding for these atomic numbers: At room temperature, all are solid but mercury is liquid; red indicates item is synthetic and does not occur naturally. ... The Boron group is the series of elements in group 13 (IUPAC style) in the periodic table. ... The carbon group is group 14 (IUPAC style) in the periodic table. ... The Nitrogen group elements (a. ... The chalcogens (with the ch pronounced with a hard c as in chemistry) are the name for the periodic table group 16 (old-style: VIB or VIA) in the periodic table. ... The halogens or halogen elements are a series of nonmetal elements from Group 17 (old-style: VII or VIIA; Group 7 IUPAC Style) of the periodic table, comprising fluorine, F, chlorine, Cl, bromine, Br, iodine, I, and astatine, At. ... Neon, like all noble gases, has a full valence (outermost) electron shell. ... A period 1 element is one of the chemical elements in the first row (or period) of the periodic table of the elements. ... A period 2 element is one of the chemical elements in the second row (or period) of the periodic table of the elements. ... A period 3 element is one of the chemical elements in the third row (or period) of the periodic table of the elements. ... A period 4 element is one of the chemical elements in the fourth row (or period) of the periodic table of the elements. ... A period 5 element is one of the chemical elements in the fifth row (or period) of the periodic table of the elements. ... A period 6 element is one of the chemical elements in the sixth row (or period) of the periodic table of the elements, including the Lanthanides. ... A period 7 element is one of the chemical elements in the seventh row (or period) of the periodic table of the elements. ... A period 8 element is one of the chemical elements in the eighth row (or period) of the periodic table of the elements. ... The alkali metals are the series of elements in Group 1 (IUPAC style) of the periodic table (excluding hydrogen in all but one rare circumstance): lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). ... The alkaline earth metals are the series of elements in Group 2 (IUPAC style) of the periodic table: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and radium (Ra) (not always considered due to its radioactivity and very short half-life). ... The lanthanide series comprises the 15 elements from lanthanum to lutetium on the periodic table, with atomic numbers 57 through 71. ... The actinide series encompasses the 15 chemical elements that lie between actinium and lawrencium on the periodic table, with atomic numbers 89 - 103[1]. The actinide series is named after actinium. ... In chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings: It commonly refers to any element in the d-block of the periodic table, including zinc, cadmium and mercury. ... This article does not cite its references or sources. ... Together with the metals and nonmetals, the metalloids (in Greek metallon = metal and eidos = sort) form one of the three categories of chemical elements as classified by ionization and bonding properties. ... Together with the metals and metalloids, a nonmetal is one of three categories of chemical elements as distinguished by ionization and bonding properties. ... The halogens or halogen elements are a series of nonmetal elements from Group 17 (old-style: VII or VIIA; Group 7 IUPAC Style) of the periodic table, comprising fluorine, F, chlorine, Cl, bromine, Br, iodine, I, and astatine, At. ... Neon, like all noble gases, has a full valence (outermost) electron shell. ... A block of the periodic table of elements is a set of adjacent groups. ... The s-block of the periodic table of elements consists of the first two groups: the alkali metals and alkaline earth metals, plus hydrogen. ... The p-block of the periodic table of elements consists of the last six groups. ... D Block is a rap group based in Yonkers, New York. ... The f-block of the periodic table of elements consists of those elements for which, in the atomic ground state, the highest-energy electrons occupy f-orbitals. ... The g-block of the periodic table of the elements consists of those elements for which, in the atomic ground state, the highest-energy electrons occupy g-orbitals. ...